Producing polymerized oils



April 7,'1942. c. M. lluLL PRODUCING POLYMERIZED OILS Filedoct. a,A19:58

Patented Apr. 7,- 1942v PRovnUcnrG roLYMEarznD olLs Carl Max Hull,Chicago, lll., assigner to Standard Oil Company, Chicago, Ill., a.corporation of indiana applicants occuper s, 193s, serial Ne. 233,911

(ci. 19e-1o) 12 Claims.

This invention relates to the conversion of hydrocarbon gases intouseful oils and particularly lubricating oils and gasoline.v One of theobjects of the invention is to convert the butanebutylene fraction ofcracking still gases into high quality lubricating oils and motor fuels.Another object of the invention is to obtain more completepolymerization of the unsaturated constituents of the four carbon atomfraction by means of a catalyst and at the same time obtain efficientutilization of the catalyst. Other objects of the invention will be setforth hereinafter.

The invention is illustrated by a drawing which shows dagrammatically acomplete layout for carrying out the process. Referring to the drawing aliqueed normally gaseous hydrocarbon stream is introduced by line I intoreaction chamber II. The hydrocarbon stream may suitably comprise amixture of butanes and butyl- -enes derived from the fractionation ofcracking still gases. As an example of such a. mixture.

I may use one containing about to 20% of isobutylene, about 20 to 30% ofnormal butylene and the remainder mostly isobutane and normal butane.The gases may be washed with caustic soda or other reagent to remove H2Sor other from the catalyst vapors in separator i9. Liquid C4hydrocarbons are withdrawn by line 20 and may be added to gasoline toadjust its vapor pressure, while catalyst vapors are withdrawn by line2l leading to compressor 22 which circulates the unused catalyst back tothe reaction chamber I I. Traces of catalyst are expelled' from theliquefied butano in separator I9 by means of heating coil 23. Heatingcoil 2d, likewise, assist in evaporating the catalyst and butanes invaporizer I5. I

The unevaporated reaction product in vaporizer I5 is withdrawn by line25 and pump 26 to reaction chamber 21. In reaction chamber 21 complexcompounds of boron iluoride are causedl to react with additional amountsof isobutylene supplied through line 28. The reaction may be sulfurcompounds they may contain and with A dilute acid to remove basicsubstances such as amines.

In the reactor II, there is also introduced by line I2 a stream ofcatalyst preferably boron fiuoride. However, boron chloride and othercatalytically active,-volatile metal halides may be employed, the commoncharacteristic of' the catalysts being that they are readily decomposedby water. The temperature of the reaction mixture in chamber II may becontrolled by cooling coil I3, a suitable temperature being between 0and 100 F., for example, 40 F. In the reaction chamber II, theisobutylene contained in thehydrocarbons is completely polymerized bythe catalyst which is used in slight excess, the reaction requiringabout 5 to 30 minutes. The

amount of catalyst may be suitably about 0.1 to 2% of the weight of thetotal hydrocarbons treated, 0.2 to 0.5% being commonly employed.

The reaction products and excess catalyst are conducted by line I4' tovaporizer I5. The pressure may be suitably reduced' by valve I6, thuspermitting a major portionof the hydrocarbon gases to vapcrze along withexcess catalyst. Thecombined vapors are conducted by line I1v tocondenser I8 where the hydrocarbon vapors are largely condensed. Thecondensate is separated j facilitated byemploying a higher temperaturethan in reaction chamber II, for example temperatures up to 200 F. butpreferably 50-100 F., the temperature being controlled by coil 29. Thehigher temperatures tend to produce relatively larger amounts ofmaterial in the gasoline boiling range. By employing an excess ofisobutylene in chamber 2 1 most of the remaining boron uoride catalystis used up in the process. The reaction product may, if desired, bewashed free of the last trace of catalyst, for example with 'sodiumcarbonate, and then conducted by line 30 to fractionator 3|. Heat issupplied to fractionator 3| by coil 32 and reux by reflux cool'- ingcoil 33. The hydrocarbon gases are dis-v charged at the top by line 34leading to. condenserV 35 and thence by line 36 and Iline I0- Y l backtothe first lreaction chamber Il. Excess isobutylene withdrawnfromreaction chamber 21 is thus recycled to the rst reaction chamber-where it is completely polymerized to higher 'A hydrocarbons.

The heavy polymers are withdrawn from the bottom of fractionator 3| byline 31 andconducted to fractionating tower 38 wherein the Aheavy oilsare separated into a. lubricating distillate withdrawn by line 39V and aheavy residual polymer withdrawn by line 40. It is preferred to operatefractionator 38 under a. vacuum of about 3 "to 50 mm. mercury pressure.The lubricating distillate vapors are condensed in condenser 4I and thedistillate may be used as a lubricating oil for internal combustionengines.

'It is especially valuable for the lubrication of Diesel engines becauseof its freedomv from car- Vbonization within the engine. It is preferredto conduct: the distillation in fractionators 3| and 3 8 to produce aDiesel lubricating distillate having\a `viscosity within the range of S.A. E.

to S. A. E. 50. The oil is characterized by agravity of about 32 A. P.I. It iswax free and l the pour point is about -30 F. for the 30 S. A.El grade. The viscosity index is about 80 to 95. 5

Oils within the viscosity range of to 40 S. A. E. are preferred.

An intermediate fraction is withdrawn from the tower' 3l by line 42 andfurther distilled in i stripper 43. A gasoline fraction is distilled oi!as v10 vapor and conducted by line 44 to condenser 4 5 leading toreceiver 46. The heavier fraction is withdrawn by line 41 leading t6receiver 4l. The heavy lubricating oil in line is collected in receiver49 and part or all of it may be blended l5 with lighter oil to produce asuperior blended lubricating voil for shock absorbers and other useswhere an oil of highviscosity index is required. Thus oil may be drawn.from receivers 48 and 49 by lines 50 and 5I respectively and blended 20in line 52. Following are the characteristics'of such a blend:

viscosity at 1oo F sec. saybou 1486 Viscosity at 210 F do 114 rviscosity index 10o 2 Flash F 250 Pour point F -30 Gravity A. P. I-..31.0 Color N. P. A-- 1 The production of distillate lubricating oil andgasoline may be augmented by recycling the light and/or heavy fractions,or both, in the manner to be described. Oil is drawn from receiver 48 byline 53 and/or from receiver 49 by line 54 35 leading to pump 55. Theoil stream then ilows by line 56 to decomposing heater 51 where it isheated to a suitable temperature for decomposition, usually within therange of '150 to 1000 F.

and preferably about 850 to 950 F. The time of 40 heating may vary froma few seconds to several minutes. For example, with a contact time of 10to 100 seconds and a temperature of 929 F.v at atmospheric pressure. theproduct contained 20 to 30% of C4 fraction, largely isobutylene. If 4the polymer oil, particularly the lighter oil, is` heated for a longertime, lower temperatures may be used. Thus, at 600 to 610 F., 21%decomposition occurred in 23 minutes. 'I'he product` was distilled at440 F. and 4 mm. mercury pressure 50 after which the residue was againdecomposed to the extent of 23% in 35 minutes. If desired, a catalystmay be employed in drum 58 to accelerate thedecomposition of the oil.Suitable catalysts are activated bentonate, fullers earth,

or aluminum oxide adsorbed on silica gel, employed at about 400 F. to600 F. I may also use boron fluoride as a catalyst in which case theboron fluoride may be introduced into the coil of heater or intocatalyst chamber 5l. Lower 60 temperatures of'the order of 200 to 400 F.are suiiicient when using this active catalyst. Repolymerization ofoleiinic products occurs on cooling and these may be separated intodesired fractions in fractionator 60. As a result of the heating, theoil is largely depolymerized to form isobutylene and other Vhydrocarbonsof intermediate boiling point. The decomposition products are conductedby line 59 to fractionator IlV where they are separated into vapors andliquids. The 7c unvaporized portion is discharged from the sys tembyline 64I and may be used to make further quantities of lubricatingoil.

Partial depolyl merization of the heavy oil from 49 may thus be made toyieldincreased. amounts of the Diesel 75 oils unsuited for gasoline orDiesel lubricating oil are collected by a trap-out plate and recycled byline B2 andpump 83 back tothe decomposing furnace. Gasoline fractionsmay be separated in the upper part of fractionator il and withdrawn byline 64 leading to cooler 65 and receiver 46. Although not usuallydesirable to do so, gasoline may also be recycled to the depolymerizingfurnace by valved line 82a. Isobutylene and other four carbon atomhydrocarbons are withdrawn by line 66 leading to pump 81 whence they aredischarged either into reaction chamber 21 by line 28 or by line 68directly into recycle' line 34- Lighter hydrocarbon gases and other xedgases are discharged from the system by vent 69. Instead of combiningthe light and heavy oils from 48 and 49 before depolymerization inheater 51, we may decompose them separately in separate `coils underoptimum conditions for each oil and combine the products in drum 58 orfractionator 60.

One of the 'important featuresl ofmy process vis the production of agasoline of high knock- ,it to suitable hydrogenation. Another importantfeature of my process is the utilization of both isobutylene and normalbutylene while producing lubricating oil of high viscosity index at thesame time.

Much of the recycle isobutylene may be polymerized in reactionchamber 21under'conditions suitable for production'of high viscosity' index-lubricating oil. Thus the temperature in reaction chamber 21 may bemaintainedat about 25 to 40 F. Temperatures within this range or ahigher reaction temperature may be maintained in chamber Il, e. g.,50'to100 F. Also, a higher concentration of catalyst will be present inchamber Il as a result of which considerable co-polymerization ofisobutylene and -normal butylene takes place with theformation ofvaluable high knock-rating motor fuels.' Likewise, a portion of thenormal butylene combines with isobutane under the iniiuence of thecatalyst to form saturat'ed hydrocarbons of high knockerating.

Although I have described my process with respect'to certain embodimentsthereof, I intend that it be limited only by the following claims.

I claim: 4

l. The process of producing lubricating oils by polymerizing oleiinhydrocarbons contained in a hydrocarbon gas mixture comprisingsubjecting saidhydrocarbon gas mixture in-liquid phase in a firstpolymerization stage to the action of an excess amount of boron fluoridecatalyst capable of forming a complex compound with oleiln hydrocarbonswhereby the major portion of said olefin hydrocarbons-is polymerized and'a substantial portion 'of said excess catalyst forms a complex compoundwith said hydrocarbons, removing unreacted hydrocarbon gases from saidcomplex compound and polymerization products, treatingpin a second stagesaid complex compound zwlth additional oleiin gases in excess 'wherebysubstantially all of said catalyst complex isV decomposed vandiadditional polymerization products are produced, introducing said excessgases into said first polymerisation` stage and listillingv saidpolymerization products to separate therefrom the desired lubricatingoil fraction.

2. The process of claim 1A wherein said desired lubnicating oil fractionis withdrawn as an intermediate boiling distillate oil having aviscosity within the range of S. A. E. 20 to 50, remainingpolymerization products are subjected to thermal y decomposition, andgaseous clef-ins produced by carbons contained in hydrocarbon gasmixtures by the action of a boron uoride catalyst capable of forming acomplex compound with said hydrocarbons the improvement comprisingtreating in a first stage said olefin'hydrocarbon mixture in liquidphase with said catalyst whereby polymerization products and catalystcomplex are formed, separating unreacted hydrocarbons from the mixtureof said polymerization products and catalyst complex, treating in asecond stage said mixture of polymerization products and izingadditional liquid butylenes by said complexfirst stage, removing butanesand unreacted butylenes from said polymer products, polymerin a secondstage, separating from said polymer products the desired intermediateviscosity lubricating oil, subjecting the remaining polymers todissociation atan elevated temperature whereby-f butylene is produced,and recycling said butylene to said second polymerization stage- 9. Theprocess of claim 8 wherein the lighter than desired polymer products aredissociated separately from the heavier than desired polymer products.

10. The process of claim 8 wherein the dissociation of said undesiredpolymer products is effected by heating to a temperature within thecatalyst complex with an excess amount of additional liquefiedhydrocarbon gases containing oleflns in a higher concentration than thatof the gas mixture first mentioned whereby said catalystI contained inysaid complex is substantially exhausted introducing said excess ofhydrocarbonsinto said'rst stage and thereafter recovering desiredpolymerization products from unreacted hydrocarbons.

7. The process of claim 6 wherein a portion of the said polymerizationproducts having an undesirable viscosity is decomposed into unsaturatedhydrocarbon gases containing a high concentration of olefin hydrocarbonsand said unsaturated hydrocarbon gases are 'introduced into said secondstage polymerization step.

8. In the process of converting butylenes into lubricating oils ofintermediate viscosity within therange of about 20 to 50S. A. E. whereina mixture of butylenes and butanes is employed as the starting material,the improvement comprising subjecting said mixture of butanes andbutylenes in liquid form to the vaction of a polymerizing catalyst intwo stages whereby said butylenes are substantially converted to heavierhydrocarbon polymer products and catalyst complex in a range of 750 to1000 F.

11. The process of claim 8 wherein the polymer products, freed ofcatalyst, are distilled to remove a motor fuel fraction, a lightdistillate lubricating oil fraction, a heavy distillate lubricating oilfraction of intermediate viscosity, and a residual lubricating oilfraction, and a portion of said light -lubricating oil fraction isblended with a portion of said heavy lubricating oil fraction to producea second blended lubricating oil as a product of the process,

12. The process of converting unsaturated hydrocarbon gases intolubricating oils and gasoline which comprises separating from said gasesa fraction consisting essentially of hydrocarbons of four carbon atomscontaining normal butylene,

' isobutylene, normal butane and isobutane, treating said four carbonatom fraction in liquid phase with an excessof boron uoride catalystwhereby said isobutylene is substantially entirely converted intolubricating oils and gasoline by polymerization and part of said normalbutylene combines with said isobutane, Yevaporating unreacted fourcarbon atom hydrocarbons from residual catalyst, gasoline andlubricating oil products, treating said-products with anexcess ofadditionall olefin hydrocarbon gases whereby the residual catalystremaining insaid products is substantially exhausted in polymerizingsaid olefins to produce further polymerization products, distilling saidproducts to separate lubricating oils and gasolinetherefrom;fractionating said products to yield a distillate` lubricatingoilfractionv having a viscosity within the range of S. A. E. 20

'to S. A. E. 40,Y subjecting remaining lubricating oil fractions todecomposition by heat whereby olefin hydrocarbon are regenerated andrecycling said regenerated olefin hydrocarbons to said secondpolymerization step.

CARL MAX HULL.

